M. P. Milazzotto

Early cleavages influence the molecular and the metabolic pattern of individually cultured bovine blastocysts.

Embryo morphokinetics suggests that the timing of the first embryonic cell divisions may predict the developmental potential of an embryo; however, correlations between embryonic morphokinetics and physiology are not clear. Here, we used RNA sequencing to determine the gene expression profile of in vitro‐produced early‐ and late‐dividing bovine embryos and their respective blastocysts, and compared these profiles to in vivo‐produced blastocysts to identify differentially expressed genes (DEGs). Principal component analysis revealed that fast‐ and slow‐dividing embryos possess similar transcript abundance over the first cleavages. By the blastocyst stage, however, more DEGs were observed between the fast‐ and slow‐dividing embryo groups, whereas blastocysts from the slow‐dividing group were more similar to in vivo‐produced blastocysts. Gene ontology enrichment analysis showed that the slow‐dividing and in vivo‐produced blastocysts shared biological processes related to groups of up‐ or down‐regulated genes when compared to the fast‐dividing blastocysts. Based on these DEG results, we characterized the relationship between developmental kinetics and energy metabolism of in vitro‐produced bovine embryos. Embryos from fast‐ and slow‐dividing groups exhibited different pyruvate and lactate metabolism at 22u2009hr post‐in vitro culture (hpc), glucose consumption at 96u2009hpc, and glutamate metabolism at 168u2009hpc. Glycogen storage was similar between cleavage‐stage and morulae groups, but was higher in the blastocysts of the slow‐dividing group. On the other hand, blastocysts of the fast‐dividing group had a higher concentration of lipids. Taken together, these data identify transcriptomic and metabolic differences between embryos with different morphokinetics, suggesting that sorting embryos based on cleavage speed may select for different metabolic patterns. Mol. Reprod. Dev. 83: 324–336, 2016.

Photobiological effect of low-level laser irradiation in bovine embryo production system

Abstract. The objectives of this study were to evaluate the effect of low-level laser irradiation (LLLI) on bovine oocyte and granulosa cells metabolism during in vitro maturation (IVM) and further embryo development. Cumulus-oocytes complexes (COCs) were subjected (experimental group) or not (control group) to irradiation with LLLI in a 633-nm wavelength and 1u2009u2009J/cm2 fluency. The COCs were evaluated after 30 min, 8, 16, and 24 h of IVM. Cumulus cells were evaluated for cell cycle status, mitochondrial activity, and viability (flow cytometry). Oocytes were assessed for meiotic progression status (nuclear staining), cell cycle genes content [real-time polymerase chain reaction (PCR)], and signal transduction status (western blot). The COCs were also in vitro fertilized, and the cleavage and blastocyst rates were assessed. Comparisons among groups were statistically performed with 5% significance level. For cumulus cells, a significant increase in mitochondrial membrane potential and the number of cells progressing through the cycle could be observed. Significant increases on cyclin B and cyclin-dependent kinase (CDK4) levels were also observed. Concerning the oocytes, a significantly higher amount of total mitogen-activated protein kinase was found after 8 h of irradiation, followed by a decrease in all cell cycle genes transcripts, exception made for the CDK4. However, no differences were observed in meiotic progression or embryo production. In conclusion, LLLI is an efficient tool to modulate the granulosa cells and oocyte metabolism.

Sperm-mediated gene transfer: effect on bovine in vitro embryo production

The technique of sperm-mediated gene transfer (SMGT) can be used to delivery exogenous DNA into the oocyte. However, it has low repeatability and produces inconsistent results. In order to optimize this technique, it is necessary to study the mechanism by which DNA enters the sperm cell and integrates in the sperm genome. Furthermore, studies must focus in the maintenance of sperm cell viability and function. The aim of this study was to evaluate different SMGT protocols of sperm electroporation or capacitation (CaI) aiming to maintain sperm viability in the production of bovine embryos in vitro. Frozen-thawed semen was divided in two experimental groups (electroporation or CaI) and one control group (non-treated cells). For the electroporation method, five different voltages (100, 500, 750, 1000 or 1500 V) with 25 μF capacitance were used. For CaI treatment, combinations of two CaI concentrations (250 nM or 500 nM), two incubation periods of sperm cells with CaI (1 or 5 min) and two incubation periods that mimicked time of sperm cell interaction with exogenous DNA molecules (1 or 2 h) were evaluated. According to our data, electroporation and CaI treatments do not prevent sperm penetration and oocyte fertilization and can be an alternative method to achieve satisfactory DNA delivery in SMGT protocols.

Low-level laser therapy on MCF-7 cells: a micro-Fourier transform infrared spectroscopy study

Abstract. Low-level laser therapy (LLLT) is an emerging therapeutic approach for several clinical conditions. The clinical effects induced by LLLT presumably scale from photobiostimulation/photobioinhibition at the cellular level to the molecular level. The detailed mechanism underlying this effect remains unknown. This study quantifies some relevant aspects of LLLT related to molecular and cellular variations. Malignant breast cells (MCF-7) were exposed to spatially filtered light from a He-Ne laser (633 nm) with fluences of 5, 28.8, and 1000u2009u2009mJ/cm2. The cell viability was evaluated by optical microscopy using the Trypan Blue viability test. The micro-Fourier transform infrared technique was employed to obtain the vibrational spectra of each experimental group (control and irradiated) and identify the relevant biochemical alterations that occurred due to the process. It was observed that the red light influenced the RNA, phosphate, and serine/threonine/tyrosine bands. We found that light can influence cell metabolism depending on the laser fluence. For 5u2009u2009mJ/cm2, MCF-7 cells suffer bioinhibition with decreased metabolic rates. In contrast, for the 1u2009u2009J/cm2 laser fluence, cells present biostimulation accompanied by a metabolic rate elevation. Surprisingly, at the intermediate fluence, 28.8u2009u2009mJ/cm2, the metabolic rate is increased despite the absence of proliferative results. The data were interpreted within the retrograde signaling pathway mechanism activated with light irradiation.

Cell viability of bovine spermatozoa subjected to DNA electroporation and DNAse I treatment.

Many mechanisms involved in sperm-mediated gene transfer (SMGT) are still unknown. It is still a matter of debate whether exogenous DNA fragments incorporated by the embryo are originated from those bound to the sperm membrane or by those that penetrated the intracellular compartment. In an attempt to elucidate the transmission mechanism of exogenous DNA molecules by sperm, some authors suggested a treatment with DNAse I to remove DNA molecules outside the sperm. But little is known regarding the effects of DNAse I treatment on sperm viability and its impact on sperm organelles. An important aspect of the SMGT technique is the amount of exogenous DNA incubated with sperm, which may influence the internalization rate. Due to the inconsistencies found in literature, this work aimed to contribute to bovine sperm physiology knowledge evaluating the effects of different DNA concentrations, electroporation, and DNAse I treatments on sperm viability characteristics, DNA uptake, and IVF. For that, the effects of different concentrations of exogenous DNA (250, 500 and 1000 ng/10(6) cells) and incubation or electroporation were tested on sperm functional characteristics and in vitro embryo production. No effect of DNA concentration was observed on uptake, plasma membrane integrity, and mitochondrial membrane potential. The addition of exogenous DNA induced a decrease on acrosomal lesion in the 500-ng group when compared to the control. Cells incubated with DNA, electroporated, and treated with DNAse I presented a deleterious influence on mitochondrial membrane potential. In vitro fertilization was made with 1000 ng of DNA, sperm cells incubated or electroporated followed by DNAse I treatment. No significant difference was found in cleavage rate. Blastocyst rates were 24.36% for the control; 19.65% for incubated; 3.5% for electroporated control; and 17.40% for electroporated. There is a significant difference in blastocyst rate between the control and electroporated control groups. The incubated group yielded five and electroporated two positive blastocysts evaluated by epifluorescence microscopy. Polymerase chain reaction screening shows 17% of positive embryos for incubation and 11% for electroporation. Fluorescence in situ hybridization showed the presence of exogenous gene in embryos. These results show that exogenous DNA molecules can be conducted by an intracellular mechanism. The SMGT protocol using electroporation and DNAse I treatment reduces sperm mitochondrial function, in vitro embryo production and increases sperm DNA fragmentation.

Morphokinetic-related response to stress in individually cultured bovine embryos

The kinetics of inxa0vitro-produced (IVP) bovine embryos is related to embryo viability, metabolism, and epigenetic patterns. Therefore, we believe that embryos with different speeds of development also respond differently to stress. In the present study, we performed global metabolic analysis (matrix-assisted laser desorption ionization time of flight mass spectrometry [MALDI-TOF]) of culture media, characterized apoptotic events (Terminal deoxynucleotidyl transferase dUTP nick end labeling [TUNEL] and caspase quantitation), and quantified transcript abundance of stress-related gene (real-time quantitative polymerase chain reaction [qRT-PCR]) in IVP bovine embryos with different developmental kinetics to investigate possible markers of stress response. For this purpose, embryos were considered fast if they presented four or more cells at 40xa0hours post insemination (hpi). Embryos presenting two cells at this time were classified as slow. Evaluations were performed at 40 hpi, 112 hpi, and 186 hpi. Metabolome analysis revealed several metabolites differentially represented between groups at all time points related with energy, lipid and amino acids metabolism, and stress response. There was no difference in TUNEL positive cells between groups in any of the time points analyzed. Nevertheless, at 112 hpi, classified as a critical phase because of the genome activation, the amount of caspase 3 and 7 and total caspase were higher in slow when compared to fast group. Transcript abundance analysis of candidate genes (GRP78, HSP60, SOD1, and MORF4L2) was also different among groups. In conclusion, IVP bovine embryos of different development speeds respond differentially to the environmental stress leading to different metabolome patterns and apoptosis activation throughout the culture.

Raman-based noninvasive metabolic profile evaluation of in vitro bovine embryos

Abstract. The timing of the first embryonic cell divisions may predict the ability of an embryo to establish pregnancy. Similarly, metabolic profiles may be markers of embryonic viability. However, in bovine, data about the metabolomics profile of these embryos are still not available. In the present work, we describe Raman-based metabolomic profiles of culture media of bovine embryos with different developmental kinetics (fast x slow) throughout the in vitro culture. The principal component analysis enabled us to classify embryos with different developmental kinetics since they presented specific spectroscopic profiles for each evaluated time point. We noticed that bands at 1076u2009u2009cm−1 (lipids), 1300u2009u2009cm−1 (Amide III), and 2719u2009u2009cm−1 (DNA nitrogen bases) gave the most relevant spectral features, enabling the separation between fast and slow groups. Bands at 1001u2009u2009cm−1 (phenylalanine) and 2892u2009u2009cm−1 (methylene group of the polymethylene chain) presented specific patterns related to embryonic stage and can be considered as biomarkers of embryonic development by Raman spectroscopy. The culture media analysis by Raman spectroscopy proved to be a simple and sensitive technique that can be applied with high efficiency to characterize the profiles of in vitro produced bovine embryos with different development kinetics and different stages of development.

The Mechanism of Oocyte Activation Influences the Cell Cycle-Related Genes Expression During Bovine Preimplantation Development

The first cleavage divisions and preimplantation embryonic development are supported by mRNA and proteins synthesized and stored during oogenesis. Thus, mRNA molecules of maternal origin decrease and embryonic development becomes gradually dependent on expression of genetic information derived from the embryonic genome. However, it is still unclear what the role of the sperm cell is during this phase and whether the absence of the sperm cell during the artificial oocyte activation affects subsequent embryonic development. The objective of this study was to determine, in bovine embryos, changes in cell cycle-associated transcript levels (cyclin A, cyclin B, cyclin E, CDC2, CDK2, and CDK4) after oocyte activation in the presence or absence of the sperm cell. To evaluate that, in vitro-produced (IVP) and parthenogenetically activated (PA) embryos (2-4 cells (2-4C), 8-16 cells (8-16C) and blastocysts) were evaluated by real-time PCR. There was no difference in cleavage and blastocyst rates between IVP and PA groups. Transcript level was higher in oocytes than in IVP and PA embryos. Cleaved PA embryos showed higher expression of cyclin A, cyclin B, cyclin E, and CDK2 and lower expression of CDC2 when compared with that from the IVP group. At the time of activation, all transcripts were expressed less in PA than in IVP embryos, whereas at the blastocyst stage, almost all genes were expressed at a higher level in the PA group. These results suggest that in both groups there is an initial consumption of these transcripts in the early stages of embryonic development. Furthermore, 8-16C embryos seem to synthesize more cell cycle-related genes than 2-4C embryos. However, in PA embryos, activation of the cell cycle genes seems to occur after the 8- to 16-cell stage, suggesting a failure in the activation process.

The effects of crocetin supplementation on the blastocyst outcome, transcriptomic and metabolic profile of in vitro produced bovine embryos

The earliest stages of embryo development are deeply influenced by reactive oxygen species (ROS), byproducts of the mitochondrial oxygen metabolism that play a key role as messengers in normal cell signal transduction and cell cycling. Despite its positive roles, the imbalance caused by the excess of ROS and an inefficient antioxidant system leads to oxidative stress, with negative consequences to the cell such as DNA damage, metabolic changes, mitochondrial stress and cell death. In the present work, crocetin - a natural antioxidant - was added to the culture media of bovine embryos to evaluate the efficiency of its antioxidant capability during embryo culture. Oocytes were inxa0vitro matured (IVM) and fertilized according to standard protocols. Embryos were cultured at 38.5u202f°C under humidified air with 5% CO2, 7% O2, and 90% N2 in Synthetic Oviduct Fluid (SOF) medium supplemented with amino acids and either 5% of FBS (SOFaa) (control group) or SOFaa supplemented with 1u202fu202fμM crocetin (crocetin group). After 5 days from the beginning of inxa0vitro culture (IVC) (day 5 - D5), embryos were transferred to individual drops of culture media. At day 7 (D7), embryos were assessed by means of blastocyst rates, morphophysiological analyzes (total cell number, ROS and mitochondrial activity levels), transcript quantitation of 47 genes and metabolomic evaluation of the culture media by Raman spectroscopy. In the crocetin group blastocyst rates were higher and embryos had increased total cell number and decreased intracellular levels of ROS. These embryos also had upregulation of genes related with response to stress and lipid metabolism (ATF4, BAX, FOXO3, GADD45A, GPX1, GPX4, HSF1, SOD2, ACACA, SREBF1 and SREBF2). Raman spectroscopy corroborated these results indicating more active lipid and amino acid production in this group. The absence of crocetin in the culture media resulted in higher ROS level, as well as up regulation of genes related to DNA damage, stress response and energy metabolism (MORF4L2, SOD1, TXN, PFKP, PGK1 and PPARGC1A). In conclusion, crocetin supplementation during culture protects embryos from oxidative stress and influences the adaptive response to stress conditions, leading to an increase in both blastocyst yield and quality, as well as changes in transcriptomic and metabolic profile of inxa0vitro produced bovine embryos.

Corrigendum to “Oxidative Stress Alters the Profile of Transcription Factors Related to Early Development on In Vitro Produced Embryos”

[This corrects the article DOI: 10.1155/2017/1502489.].